A blisk is a key component of a new generation aeroengine, and compared with traditional aeroengine blades, the application of the blisk facilitates performance improvement, mechanism simplification, mass reduction, reliability and durability improvements of the aeroengine. Polishing process, as the last procedure in the machining of the whole blisk, directly influences the surface quality and aerodynamic performance of the blisk. Since the blisk has a complicated structure and its material is also hard to machine, the machining of the blisk is very difficult. Although an electronic beam polishing, an electrolytic polishing and other polishing methods have appeared in China, they all have a low degree of automation and a low manual operation efficiency, and can hardly ensure the machining accuracy and surface quality, and are apt to cause damages to the blisk.
With the rapid development of the abrasive belt grinding technologies and devices, an abrasive belt grinding and polishing machine tool has developed into a fine machining device having a high machining efficiency, a strong adaptability, a wide application range, a low use-cost and being safe and convenient to operate. Its advantages are obvious especially for grinding and polishing thin walled structural members having a complex curved surface such as aeroengine blades, small-size complex profiles, and a junction between surfaces. Generally speaking, in an abrasive belt grinding and polishing machine tool, an abrasive belt is driven by a driving device to move, and the abrasive belt is tensioned by a certain number of tensioning wheels, and is supported by a contact wheel or a support plate to generate a contact pressure to a workpiece and form a cutting angle, to finish grinding and polishing of the workpiece.
In recent years, numerical control abrasive belt grinding machines have successfully realized polishing and grinding on some parts having complex curved surfaces such as turbine blades, aeroengine blades and gun clampers, and the abrasive belt also has good machining characteristics for materials which are difficult to machine. However, since the blisk has the characteristics such as a flow path profile and a blade profile thereof are both free curved surfaces, the channel between blades is narrow, the blade is thin and is easy to deform, and the material of the blisk is difficult to machine, the conventional grinding method cannot address issues such as the whole profile grinding of the blisk, the interference between a grinding tool and a workpiece in the grinding process, and the meshing between the grinding curved surfaces. Further, grinding textures on the surface of the blisk are generally transverse textures, however, the study shows that if the blisk has longitudinal textures, its fatigue strength may be greatly improved compared with the blades made by a conventional grinding method.
The results of the above study have not yet formed a very good abrasive belt grinding and polishing device to deal with the grinding and polishing of workpieces having a complex surface and an irregular-shaped structure represented by the blisk of the aeroengine, and a specialized abrasive belt grinding and polishing machine capable of machining such kind of workpieces has not been applied domestically yet. The following requirements have not been met yet such as realizing the whole profile grinding of the blisk of the aeroengine, eliminating the interference in grinding and achieving the longitudinal grinding to improve mechanical properties such as the fatigue strength.